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A Physicist Who Denies Dark Matter

nautil.us

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Re: A Physicist Who Denies Dark Matter

#61

Post by platz »

jcroll wrote: post #45
agentgt wrote: post #25

This almost an exact duplicate: http://cosmos.nautil.us/short/144/the-physicist-who-denies-t... and original HN comments here: https://news.ycombinator.com/item?id=13743439 Do people not search Agolia before posting? Is it acceptable to repost things? (I'm not HN expert).

Actually what's disturbing (and I am a paid subscriber to nautil.us) is that nautil.us is duplicating content. They took that old interview and passed it off as new content in their latest edition. Not really fair to us paying readers!

the domains are different. is "cosmos" a separate thing?

Re: A Physicist Who Denies Dark Matter

#62

Post by euyyn »

_ph_ wrote: post #49
vivekd wrote: post #41

Earlier quoted context omitted.

>How do you explaining gravitational lensing with no visible mass, without dark matter? Black holes? The physicist says: >What struck me was some regularity in the anomaly. The rotational velocities were not just larger than expected, they became constant with radius. Why? Sure, if there was dark matter, the speed of stars would be greater, but the rotation curves, meaning the rotational speed drawn as a function of…

>>How do you explaining gravitational lensing with no visible mass, without dark matter? >Black holes? Well, black holes are not really black, you can see their accretion disk. Also, a centralized huge mass would create a different velocity profile from what we are seeing. So black holes are pretty much out.

> Also, a centralized huge mass would create a different velocity profile from what we are seeing.

Doesn't need to be centralized, no? They can orbit the galaxy as the other bodies.

Re: A Physicist Who Denies Dark Matter

#64

Post by gaius »

shakna wrote: post #2

The title is irritating. This is an interview with Milgrom, covering the man more than MOND. But, dark matter isn't something to be denied. Because it isn't understood yet, to the point where we can doubt its existence. We don't have all the answers yet, where denial rejects something as patently false. But, "The man who has an alternative to Dark Matter", is a far less attractive title for those clicks.

The use of the word "deny" is deliberate, it's used to invoke the phrase "holocaust denier" to smear the person you're accusing of it. An underhanded tactic from the author of this hit-piece.

Re: A Physicist Who Denies Dark Matter

#65

Post by joeberon »

maratd wrote: post #51
RockyMcNuts wrote: post #11

How do you explaining gravitational lensing with no visible mass, without dark matter? In other words situations where we see twin images of a very distant galaxy because light curves around intervening mass, without sufficient mass observable to explain the deflection? I was under the impression that we could map dark matter localized to a precision that tended to rule out measurement error or a general divergence f…

When we're confronted with something we can't explain using our existing equations and theories, the conclusion is that there must be some mysterious thing there that fixes our current equations and makes them work again? A thing we can't detect or see or have any other evidence of ... other than our equations and theories need that thing there for them to work? > In other words situations where we see twin images of…

Firstly, they function well enough to predict that gravitational waves exist, the ones which we measured being produced by an extreme gravitational event.

Secondly, many other areas of physics have worked this out. The prime example of Quantum Field Theory and the Standard Model, which has been incredibly successful in predicting the existence of new types of particles from purely mathematical equations and theories (and trust me that stuff is pretty damn abstract, even compared to General Relativity)

It is of course a possibility, although you make it sound somewhat obvious, as if physicists just haven't bothered to question that the widely-regarded theories might be wrong. I assure you this is not the case; there are no politics involved in this kind of research which is stopping people presenting questions such as "are we sure our current models are correct?"

In cases like this, it is safe to assume that researchers have already explored any ideas you could come up with, especially the particularly simple ones...

Re: A Physicist Who Denies Dark Matter

#66

Post by gaius »

douche wrote: post #36
hwillis wrote: post #34

Earlier quoted context omitted.

>One of the recent most convincing things was the bullet cluster as described here.[1] We saw two galaxies collide where the "observed" matter actually underwent a collision but the gravitational lensing kept moving un-impeded which matches the belief that the majority of mass in a galaxy is collisionless dark matter that felt no colliding interaction and passed right on through bringing the bulk of the gravitational…

We don't understand how matter acrually works on a large scale. Inventing imaginary terms that we can't observe to satisfy the equations in the models to match the observed reality seems a poor practice.

Right it's like when people say, I don't believe in Creation, that stuff is just nonsense. And you say, so what's your alternative theory then? And they reply, well there was a "big bang" and everything just sort of appeared, for no reason. Really, that's the alternative explanation?

Re: A Physicist Who Denies Dark Matter

#67

Post by jrvidal »

maratd wrote: post #51
RockyMcNuts wrote: post #11

How do you explaining gravitational lensing with no visible mass, without dark matter? In other words situations where we see twin images of a very distant galaxy because light curves around intervening mass, without sufficient mass observable to explain the deflection? I was under the impression that we could map dark matter localized to a precision that tended to rule out measurement error or a general divergence f…

When we're confronted with something we can't explain using our existing equations and theories, the conclusion is that there must be some mysterious thing there that fixes our current equations and makes them work again? A thing we can't detect or see or have any other evidence of ... other than our equations and theories need that thing there for them to work? > In other words situations where we see twin images of…

FWIW, this approach is popular because it has worked pretty well in the past.

https://en.wikipedia.org/wiki/Neutrino

Re: A Physicist Who Denies Dark Matter

#68

Post by jcroll »

platz wrote: post #61
jcroll wrote: post #45

Earlier quoted context omitted.

Actually what's disturbing (and I am a paid subscriber to nautil.us) is that nautil.us is duplicating content. They took that old interview and passed it off as new content in their latest edition. Not really fair to us paying readers!

the domains are different. is "cosmos" a separate thing?

It's actually my favorite part of nautil.us but has not been updated lately so maybe I am the only one :(

It is a subsection (as it is a subdomain) but it's linked to directly from their main page. Consider it a magazine within the main publication.

Re: A Physicist Who Denies Dark Matter

#69

Post by Symmetry »

solotronics wrote: post #6

the non light emitting mass could be Dyson spheres of space based computers

Dyson spheres emit lots of light, just at lower temperatures than that of the star they encompass. You're basically running a Carnot engine with the heat reservoir at the temperature of the star, some number of thousand degrees, and the cold reservoir at a few degrees kelvin.

Re: A Physicist Who Denies Dark Matter

#70

Post by jrvidal »

douche wrote: post #9

Dark matter appears, to a layman with some historical knowledge, as nothing more than modern day epicycles. When we can't explain something with the models we have, and have to invent magic terms to balance the equations, that indicates that we really don't know what the fuck is going on.

On the other hand:

https://en.wikipedia.org/wiki/Neutrino

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